Amendment procedures

Flexible constitutions

A flexible constitution is one that may be amended by a simple act of the legislature, in the same way as it passes ordinary laws. The 'uncodified' constitution of the United Kingdom consists partly of important statutes, and partly of certain unwritten conventions. The statutes that make up the UK constitution can be amended by a simple act of Parliament. UK constitutional conventions are held to evolve organically over time.

Special majority

The constitutions of a great many nations provide that they may be amended by the legislature, but only by a special, extra large majority of votes cast (also known as a supermajority, or a "qualified" or "weighted" majority). This is usually a majority of two-thirds the total number of votes cast. In a bicameral parliament it may be required that a special majority be achieved in both chambers of the legislature. In addition, many constitutions require a that an amendment receive the votes of a minimum absolute number of members, rather than simply the support of those present at a meeting of the legislature which is in quorum.

Successive majorities

Some jurisdictions require that an amendment be approved by the legislature on two separate occasions during two separate but consecutive terms, with a general election in the interim. Under some of these constitutions there must be a dissolution of the legislature and an immediate general election on the occasion that an amendment is adopted for the first time.

Special requirements

An amendment to the United States Constitution must be ratified by three-quarters of either the state legislatures, or of constitutional conventions specially elected in each of the states, before it can come into effect.

Prohibited amendments

Some states restrict the kind of amendment to which they may be subject. This is usually to protect characteristics of the state considered sacrosanct, such as the democratic form of government or the protection of fundamental human rights.

Article Five of the U.S. Constitution prohibits any amendments which would deprive a state of its "equal Suffrage in the Senate" without that state's consent.

Section 284 of Article 18 of the Alabama State Constitution states that legislative representation is based on population, and any amendments are precluded from changing that.

Form of changes to the text

The manner in which constitutional amendments are finally recorded takes two main forms. In most jurisdictions, amendments to a constitution take the form of revisions to the main body of the original text. Thus once an amendment has become law, portions of the original text may be deleted or new articles may be inserted among existing ones. The second, less common method, is for amendments to be appended to the end of the main text in the form of special articles of amendment, leaving the body of the original text intact. Although the wording of the original text is not altered, the "doctrine of implied repeal" applies. In other words, in the event of conflict, an article of amendment will usually take precedence over the provisions of the original text, or of an earlier amendment. Nonetheless, there may still be ambiguity as to whether an amendment is intended to supersede an existing article in the text or merely to supplement it. An article of amendment may, however, explicitly express itself as having the effect of repealing a specific existing article.